Table 2.
Baseline characteristics of the development group and validation group (n = 599).
| Group | Development (n = 420) | Validation (n = 179) | P |
| Age (median, Q1–Q3) | 64.00 (59.00–69.00) | 65.00 (60.00–70.00) | .264 |
| BMI, kg/m2 (Median, Q1–Q3) | 23.00 (21.00–25.00) | 23.00 (21.00–25.00) | .746 |
| Smoking history | .835 | ||
| No | 219 (52.14%) | 95 (53.07%) | |
| Yes | 201 (47.86%) | 84 (46.93%) | |
| Dinking history | .659 | ||
| No | 250 (59.52%) | 110 (61.45%) | |
| Yes | 170 (40.48%) | 69 (38.55%) | |
| Sex | .219 | ||
| Female | 80 (19.05%) | 42 (23.46%) | |
| Male | 340 (80.95%) | 137 (76.54%) | |
| DM | .588 | ||
| No | 389 (92.62%) | 168 (93.85%) | |
| Yes | 31 (7.38%) | 11 (6.15%) | |
| HTN | .289 | ||
| No | 293 (69.76%) | 117 (65.36%) | |
| Yes | 127 (30.24%) | 62 (34.64%) | |
| COPD | .495 | ||
| No | 412 (98.10%) | 174 (97.21%) | |
| Yes | 8 (1.90%) | 5 (2.79%) | |
| CHD | .938 | ||
| No | 403 (95.95%) | 172 (96.09%) | |
| Yes | 17 (4.05%) | 7 (3.91%) | |
| Stroke history | .349 | ||
| No | 393 (93.57%) | 171 (95.53%) | |
| Yes | 27 (6.43%) | 8 (4.47%) | |
| Dysphagia | .188 | ||
| No | 377 (89.76%) | 154 (86.03%) | |
| Yes | 43 (10.24%) | 25 (13.97%) | |
| Tumor location | .224 | ||
| Upper | 20 (4.76%) | 15 (8.38%) | |
| Middle | 250 (59.52%) | 103 (57.54%) | |
| Lower | 150 (35.71%) | 61 (34.08%) | |
| ASA | .932 | ||
| 1 | 274 (65.24%) | 121 (67.60%) | |
| 2 | 115 (27.38%) | 45 (25.14%) | |
| 3 | 25 (5.95%) | 11 (6.15%) | |
| 4 | 6 (1.43%) | 2 (1.12%) | |
| Operation time, h | 3.90 (2.90–4.60) | 3.60 (2.80–4.50) | .761 |
| Tumor size, cm | 3.50 (2.30–4.50) | 3.00 (2.20–4.35) | .720 |
| Lymph no. | 20.00 (14.00–26.00) | 21.00 (15.00–27.50) | .351 |
| Type of operation | .278 | ||
| Open operation | 200 (47.62%) | 81 (45.25%) | |
| MIE | 170 (40.48%) | 68 (37.99%) | |
| RAMIE | 50 (11.90%) | 30 (16.76%) | |
| Anastomosis | .269 | ||
| Cervical | 296 (70.48%) | 118 (65.92%) | |
| Intrathoracic | 124 (29.52%) | 61 (34.08%) | |
| Tstage | .623 | ||
| TIS | 16 (3.81%) | 8 (4.47%) | |
| T1 | 93 (22.14%) | 33 (18.44%) | |
| T2 | 111 (26.43%) | 50 (27.93%) | |
| T3 | 189 (45.00%) | 86 (48.04%) | |
| T4 | 11 (2.62%) | 2 (1.12%) | |
| Nstage | .936 | ||
| N0 | 250 (59.52%) | 104 (58.10%) | |
| N1 | 110 (26.19%) | 49 (27.37%) | |
| N2 | 53 (12.62%) | 24 (13.41%) | |
| N3 | 7 (1.67%) | 2 (1.12%) | |
| NC | .935 | ||
| No | 365 (86.90%) | 156 (87.15%) | |
| Yes | 55 (13.10%) | 23 (12.85%) |